The present invention relates to an optical component, such as a non-reciprocal element, which is favorable to be used mainly as an optical passive component for optical communication, and a method of manufacturing the optical component.
Conventionally, an optical isolator has been used as an optical component for optical communication.
As will later be described more in detail, a conventional optical isolator generally comprises first and second polarizers, a Faraday rotator, a compensator, first and second substrates. In a method of manufacturing the conventional optical isolator, the first polarizer, the Faraday rotator and the compensator are cut into a predetermined size and then fixed by an adhesive on the first substrate which is cut in a uniform size. Then, the second polarizer is adhered on the first substrate by adhesive. Thereafter, the second substrate is adhered on the first polarizer, the Faraday rotator, the compensator, and the second polarizer from the side thereof opposite to that of the first substrate.
Another conventional optical isolator comprises a cylindrical metallic housing, primary and secondary polarizers, a Faraday rotator, and a ring-type magnet. Further, the metallic housing is composed in combination of a tubular housing member and a cap-type housing member. The primary polarizer, the Faraday rotator and the ring-type magnet is fixed in the tubular housing member while the secondary polarizer is fixed in the cap-type housing member. The ring-type magnet is inserted at a peripheral portion of the Faraday rotator.
However, the method of manufacturing the conventional optical isolator has a problem of requiring a lot of working time for assembling optical elements. Further, in the event of mounting the optical elements on the first substrate by a pair of tweezers, the optical elements are attracted to each other by surface tension of the adhesive, the solder or the glass solder. Accordingly, characteristics of the conventional optical isolator may adversely affected because of deposition of adhesive, solder or glass solder on an optical surface or slant and inclination of the optical elements.
Further, in the another conventional optical isolator, the ring-type magnet is located to enclose the Faraday rotator in order to provide magnetic field to the Faraday rotator. However, much cost is required for processing the ring-type magnet.
Furthermore, for assembling the conventional optical isolators into an LD module, and the like, by welding, whole of the optical elements are inserted in a metallic case. However, it is difficult and requires much cost to fabricate the metallic case which is smaller in size. Accordingly, it is difficult to fabricate the conventional optical isolators in a small size at a low cost.
It is therefore an object of the present invention to provide an optical component, such as a non-reciprocal element, which has excellent optical characteristics and excellent mass-producibility and in which each optical element thereof is fixed securely.
It is another object of the present invention to provide a method of manufacturing the optical component which has excellent optical characteristics and excellent mass-producibility, and in which each optical element thereof is fixed securely.
Other objects of the present invention will become clear as the description proceeds.
In an optical component of the present invention when a polarizer or a Faraday rotator is fixed on a substrate, it is not required to cut each of the above-mentioned optical elements into pieces. On the contrary, the optical component of the present invention is formed as follows. Namely, at first, the substrate is cut into a strip having a predetermined width while each of the optical elements is cut into a strip having a predetermined width. Next, each of the strip-shaped optical elements is mixed on the strip-shaped substrate. Then, the substrate and the optical elements fixed thereon are cut simultaneously to have a predetermined size. Besides, a birefringent crystal can be alternatively used as the polarizer.
The method of manufacturing the optical component of the present invention are carried out, as described below. At first, primary and secondary substrates are cut into a strip having a predetermined width while each of a polarizer or a birefringent crystal, and a Faraday rotator is cut into a strip having a predetermined width. Next, each of the strip-shaped polarizer or the strip-shaped birefringent crystal, and the strip-shaped Faraday rotator is fixed on the strip-shaped primary substrate. Then, secondary substrate cut into a strip having a predetermined width is fixed on the strip-shaped polarizer or the strip-shaped birefringent crystal, and the strip-shaped Faraday rotator from another sides thereof opposite to the sides on which the primary substrate is fixed. Thereafter, the optical component is produced by cutting the optical elements and the primary and secondary substrates in a predetermined size simultaneously.
Further, according to an optical component of the present invention, an optical component consisting of a non-reciprocal element, such as an optical isolator, an optical circulator, and the like is provided. In the optical component, a Faraday rotator can be supplied with magnetic field without using a ring-shaped magnet by enclosing a polarizer and the Faraday rotator with four pieces of plate-like magnets. A processing cost of a plate-like magnet is smaller than that of a ring type magnet. It is therefore possible to provide an optical component which can be manufactured at a lower cost.
Furthermore, according to an optical component of the present invention, an optical component consisting of a non-reciprocal element, such as an optical isolator, an optical circulator, and the like is provided. In the optical component, it is not necessary to contain a polarizer and a Faraday rotator in a metallic housing by fixing the polarizer and the Faraday rotator on a substrate by the use of magnets which can be welded. Since the metallic housing is not required for the optical component, reduction of costs and down sizing of the optical component can be achieved. Besides, a birefringent crystal can be alternatively used as the polarizer.
Moreover, according to a method of manufacturing an optical component of the present invention, a semi-manufactured article of the optical component is cut into a strip of a predetermined width and then fixed on a substrate. Consequently, it becomes easy to make an optical isolator, an optical circulator, and the like be positioned by an instrument. Therefore, it is possible to reduce not only slant or inclination of the optical component but also unnecessary deposition of an adhesive to the optical component. Accordingly, an optical component consisting of a non-reciprocal element, such as an optical isolator, an optical circulator, and the like, can be manufactured to have stable and reliable characteristics.
In addition, according to a method of manufacturing an optical component of the present invention, the strip-shaped semi-manufactured article of the optical component may be fixed on a glass substrate. Thereafter, the strip-shaped semi-manufactured article of the optical component and the glass substrate may be cut simultaneously. Accordingly, it is possible to reduce man-hour for manufacturing the optical component to a large extent.
Namely, according to an aspect of the present invention, there is provided an optical component comprising: polarizing means, a Faraday rotator and a substrate, the polarizing means and the Faraday rotator being fixed on the substrate by at least two surfaces except for each optical surface thereof, respectively, the substrate consisting of magnet which can be welded.
The polarizing means may be composed of a polarizer or a birefringent crystal.
The optical component may be for use in a non-reciprocal element, such as an optical isolator and an optical circulator.
According to another aspect of the present invention, there is provided a method of manufacturing an optical component, the method comprising the steps of: preparing first lengthy consisting of a material for polarizing means; preparing second lengthy consisting of a material for a Faraday rotator; fixing the first lengthy and the second lengthy on a substrate; cutting the first lengthy, the second lengthy and the substrate through the whole thereof into a plurality of pieces each having a predetermined size; and each of the a plurality of pieces being used as the optical component.
The polarizing means may be composed of two polarizers or two birefringent crystals.
The substrate may consist of magnet which can be welded.
According to still another aspect of the present invention, there is also provided a method of manufacturing an optical component, the method comprising the steps of: preparing first lengthy consisting of a material for polarizing means; preparing second lengthy consisting of a material for a Faraday rotator; fixing the first lengthy and the second lengthy by two substrate with the first lengthy and the second lengthy being interposed therebetween; cutting the first lengthy, the second lengthy and the two substrate through the whole thereof into a plurality of pieces each having a predetermined size; and each of the a plurality of pieces being used as the optical component.